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authorJason Wessel <jason.wessel@windriver.com>2009-05-11 15:24:09 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2009-06-15 21:44:45 -0700
commit98fcb5f78165b8a3d93870ad7afd4d9ebbb8b43a (patch)
treeed64298e8b6bf47ba9c57db298e732429f7f669e
parent87c1edd217a6742e48028db6664d7763de0449f6 (diff)
USB: serial: usb_debug,usb_generic_serial: implement sysrq and serial break
The usb_debug driver was modified to implement serial break handling by using a "magic" data packet comprised of the sequence: 0x00 0xff 0x01 0xfe 0x00 0xfe 0x01 0xff When the tty layer requests a serial break the usb_debug driver sends the magic packet. On the receiving side the magic packet is thrown away or a sysrq is activated depending on what kernel .config options have been set. The generic serial driver was modified as well as the usb serial headers to generically implement sysrq processing in the same way the non usb uart based drivers implement the sysrq handling. This will allow other usb serial devices to implement sysrq handling as desired. The new usb serial functions are named similarly and implemented similarly to the uart functions as follows: usb_serial_handle_break <-> uart_handle_break usb_serial_handle_sysrq_char <-> uart_handle_sysrq_char Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/serial/generic.c56
-rw-r--r--drivers/usb/serial/usb_debug.c39
-rw-r--r--include/linux/usb/serial.h8
3 files changed, 91 insertions, 12 deletions
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index c919686521f..9fccc26235a 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -339,6 +339,7 @@ int usb_serial_generic_write(struct tty_struct *tty,
/* no bulk out, so return 0 bytes written */
return 0;
}
+EXPORT_SYMBOL_GPL(usb_serial_generic_write);
int usb_serial_generic_write_room(struct tty_struct *tty)
{
@@ -351,7 +352,9 @@ int usb_serial_generic_write_room(struct tty_struct *tty)
spin_lock_irqsave(&port->lock, flags);
if (serial->type->max_in_flight_urbs) {
if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
- room = port->bulk_out_size;
+ room = port->bulk_out_size *
+ (serial->type->max_in_flight_urbs -
+ port->urbs_in_flight);
} else if (serial->num_bulk_out && !(port->write_urb_busy)) {
room = port->bulk_out_size;
}
@@ -385,7 +388,8 @@ int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
}
-static void resubmit_read_urb(struct usb_serial_port *port, gfp_t mem_flags)
+void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
+ gfp_t mem_flags)
{
struct urb *urb = port->read_urb;
struct usb_serial *serial = port->serial;
@@ -406,25 +410,28 @@ static void resubmit_read_urb(struct usb_serial_port *port, gfp_t mem_flags)
"%s - failed resubmitting read urb, error %d\n",
__func__, result);
}
+EXPORT_SYMBOL_GPL(usb_serial_generic_resubmit_read_urb);
/* Push data to tty layer and resubmit the bulk read URB */
static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
{
struct urb *urb = port->read_urb;
struct tty_struct *tty = tty_port_tty_get(&port->port);
- int room;
+ char *ch = (char *)urb->transfer_buffer;
+ int i;
+
+ if (!tty)
+ goto done;
/* Push data to tty */
- if (tty && urb->actual_length) {
- room = tty_buffer_request_room(tty, urb->actual_length);
- if (room) {
- tty_insert_flip_string(tty, urb->transfer_buffer, room);
- tty_flip_buffer_push(tty);
- }
+ for (i = 0; i < urb->actual_length; i++, ch++) {
+ if (!usb_serial_handle_sysrq_char(port, *ch))
+ tty_insert_flip_char(tty, *ch, TTY_NORMAL);
}
+ tty_flip_buffer_push(tty);
tty_kref_put(tty);
-
- resubmit_read_urb(port, GFP_ATOMIC);
+done:
+ usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
}
void usb_serial_generic_read_bulk_callback(struct urb *urb)
@@ -515,10 +522,35 @@ void usb_serial_generic_unthrottle(struct tty_struct *tty)
if (was_throttled) {
/* Resume reading from device */
- resubmit_read_urb(port, GFP_KERNEL);
+ usb_serial_generic_resubmit_read_urb(port, GFP_KERNEL);
}
}
+int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
+{
+ if (port->sysrq) {
+ if (ch && time_before(jiffies, port->sysrq)) {
+ handle_sysrq(ch, tty_port_tty_get(&port->port));
+ port->sysrq = 0;
+ return 1;
+ }
+ port->sysrq = 0;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
+
+int usb_serial_handle_break(struct usb_serial_port *port)
+{
+ if (!port->sysrq) {
+ port->sysrq = jiffies + HZ*5;
+ return 1;
+ }
+ port->sysrq = 0;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_serial_handle_break);
+
void usb_serial_generic_shutdown(struct usb_serial *serial)
{
int i;
diff --git a/drivers/usb/serial/usb_debug.c b/drivers/usb/serial/usb_debug.c
index a9427a8b867..614800972dc 100644
--- a/drivers/usb/serial/usb_debug.c
+++ b/drivers/usb/serial/usb_debug.c
@@ -17,6 +17,17 @@
#define URB_DEBUG_MAX_IN_FLIGHT_URBS 4000
#define USB_DEBUG_MAX_PACKET_SIZE 8
+#define USB_DEBUG_BRK_SIZE 8
+static char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = {
+ 0x00,
+ 0xff,
+ 0x01,
+ 0xfe,
+ 0x00,
+ 0xfe,
+ 0x01,
+ 0xff,
+};
static struct usb_device_id id_table [] = {
{ USB_DEVICE(0x0525, 0x127a) },
@@ -39,6 +50,32 @@ static int usb_debug_open(struct tty_struct *tty, struct usb_serial_port *port,
return usb_serial_generic_open(tty, port, filp);
}
+/* This HW really does not support a serial break, so one will be
+ * emulated when ever the break state is set to true.
+ */
+static void usb_debug_break_ctl(struct tty_struct *tty, int break_state)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ if (!break_state)
+ return;
+ usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
+}
+
+static void usb_debug_read_bulk_callback(struct urb *urb)
+{
+ struct usb_serial_port *port = urb->context;
+
+ if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
+ memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
+ USB_DEBUG_BRK_SIZE) == 0) {
+ usb_serial_handle_break(port);
+ usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
+ return;
+ }
+
+ usb_serial_generic_read_bulk_callback(urb);
+}
+
static struct usb_serial_driver debug_device = {
.driver = {
.owner = THIS_MODULE,
@@ -48,6 +85,8 @@ static struct usb_serial_driver debug_device = {
.num_ports = 1,
.open = usb_debug_open,
.max_in_flight_urbs = URB_DEBUG_MAX_IN_FLIGHT_URBS,
+ .break_ctl = usb_debug_break_ctl,
+ .read_bulk_callback = usb_debug_read_bulk_callback,
};
static int __init debug_init(void)
diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index e2938fd179e..e29ebcf3287 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -15,6 +15,7 @@
#include <linux/kref.h>
#include <linux/mutex.h>
+#include <linux/sysrq.h>
#define SERIAL_TTY_MAJOR 188 /* Nice legal number now */
#define SERIAL_TTY_MINORS 254 /* loads of devices :) */
@@ -99,6 +100,7 @@ struct usb_serial_port {
char throttled;
char throttle_req;
char console;
+ unsigned long sysrq; /* sysrq timeout */
struct device dev;
};
#define to_usb_serial_port(d) container_of(d, struct usb_serial_port, dev)
@@ -301,6 +303,12 @@ extern void usb_serial_generic_unthrottle(struct tty_struct *tty);
extern void usb_serial_generic_shutdown(struct usb_serial *serial);
extern int usb_serial_generic_register(int debug);
extern void usb_serial_generic_deregister(void);
+extern void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
+ gfp_t mem_flags);
+extern int usb_serial_handle_sysrq_char(struct usb_serial_port *port,
+ unsigned int ch);
+extern int usb_serial_handle_break(struct usb_serial_port *port);
+
extern int usb_serial_bus_register(struct usb_serial_driver *device);
extern void usb_serial_bus_deregister(struct usb_serial_driver *device);